Molecular Interactions between Rubber and Asphalt

Abstract

The analysis of the interactions between rubber and asphalt was carried out. The swelling rate and equilibrium of rubber penetration with the selected asphalt components were found to be dependent on these components and the rubber content in asphalt. At fixed conditions of stirring asphalt with rubber, the equilibrium swell value decreases with the increase in rubber content. From the gel permeation chromatography (GPC) analysis, it follows that the lighter asphalt components penetrate more readily into the internal matrix of the polymer. The gas chromatography-mass spectrometry (GC-MS) study allowed us to assess which components penetrated from asphalt into the rubber and which moved from rubber to asphalt. It has been found that of the nonpolar components, the n-alkanes and n-alkylbenzenes, possess the highest propensity to penetrate into rubber particles. Preferential absorption of the compounds with linear aliphatic chains into the rubber suggests that these components have a good compatibility with the linear polymeric skeleton of the rubber. During immersion of the rubber in hot asphalt, the fatty acids, which are the components of the curing system of the polymer, move from rubber to asphalt, and they are most probably concentrated in the naphthene-aromatic fraction of the asphalt. The electron paramagnetic resonance (EPR) study confirmed the effect of the immersion time of rubber in asphalt and of the shear on the swelling rate.

New Study on Improved Performance of Paving Asphalts by Crumb Rubber and Polyethylene Modification

“…However, blending the admixture of CR/ LDPE in asphalt has decreased the saturate percentage at 10.0% dose percentage comparing with the percentage dose of 3.0% and 5.0%. This corresponds also to the findings of Irena et al [31] who have shown that when the CR content in asphalt is lower, the extent of swelling is greater, suggesting that it is not the whole asphalt material but only some of the small amounted components which contribute to the swelling of the CR. In contrast, the percentage amount of (i) resins and aromatics of the CR-modified asphalt at CR dose of (3.0%, 5.0% & 10.0%) have been increased, which can be attributed to the fact that CR powder had been degraded during interaction and part of the vulcanized rubber had gone desulfuration.…”

“…Semi powdered CR will therefore disperse and dissolve more rapidly than porous pellets [30]. The benefit of using CR with asphalt binders include improved temperature susceptibility, reduction in reflective cracking of the pavement, noise reduction and reduce propensity for failure at low pavement temperature [31].…”

“…The extension of immersion time enhances the liquefied asphalt to penetrate into the matrix of polymer and swelling increases. The extent of rubber swelling in asphalt varies according to (i) temperature and time of rubber-asphalt contact, chemical composition of asphalt, rubber type, and particle size [31]. Table 6 shows the chemical components of the modified asphalt and their changes in percentages (%) as due to the physical interactions occurred by the additives within the final modified asphalt products.…”

Investigation of the Physical and Molecular Properties of Asphalt Binders Processed with Used Motor Oils

“…When CRM is added to asphalt, the lighter asphalt components penetrate into the internal matrix of the rubber as they have good compatibility with the linear skeleton of the rubber [11]. Chemical composition of asphalt and its viscosity determine the CRM swell size and rate.…”

Modul elastičnosti asfalta s bitumenom modificiranim gumenim granulatom kao vezivom

“…This enables partial dissolution of the crumb rubber, which thus becomes an active modifying ingredient in the bitumen. This crumb rubber modified bitumen, which has beneficial engineering characteristics of both ingredients, is then used for asphalt mixtures [3,4,6]. Currently, the characteristics of asphalt mixtures made using the wet process are better compared to the dry process [7,8].…”